JPS6249107A - Liquid fuel combustion device - Google Patents

Abstract

PURPOSE:To prevent an incomplete combustion by a method wherein a nozzle for injecting liquid fuel at a desired injection angle is arranged at a closed end part of a combustion chamber, an inner surface of a circumferential wall of the combustion chamber is formed at the substantial same angle as the injection angle of the nozzle, and a burner code is arranged in a coaxial relation with the nozzle. CONSTITUTION:When liquid fuel is injected into the burner cone 11, a small diameter part acting as a base end of the burner cone 11 shows a negative pressure due to the flow of injection, the non-ignited gas staying at the front part is recirculated by a flow of the fuel from the extremity end of the burner cone 11 to its base end part and then the combustion is promoted to prevent an incomplete combustion. In turn, as a supplying pressure of the liquid fuel decreased to meter the combustion condition, the fuel injected from the nozzle 7 shows a rough particle size, resulting in that the fuel is not sufficiently dispersed in a forward direction and then dripped to the inner surface of the burner cone 11. This burner cone 11 is heated with the combustion flame or radiation heat from the flame holder 12, so that the dropped large-size particle fuel is rapidly gasified and mixed with the combustion air fed from the air holes 5 to perform a combustion and thus an incomplete combustion of the fuel is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a liquid fuel combustion device that atomizes and burns liquid fuel using a nozzle.

[Technical background of the invention and its problems]

2. Description of the Related Art Liquid fuel combustion devices are known that pressurize liquid fuel and inject it from a nozzle to atomize it into particles, which are then combusted. In a combustion device having such a structure, the strength of the combustion state is adjusted by the injection pressure of the liquid fuel.

By the way, conventional liquid fuel combustion devices have a structure in which a burner is disposed at the bottom of a combustion chamber formed in the shape of a cylinder with a bottom, and liquid fuel is atomized and injected from the burner to be combusted. (For example, see Utility Model Application Publication No. 59-134719.) Therefore, liquid! 111! When the liquid fuel particles become coarser by lowering the pressure of the I fuel and restricting the combustion state,
It was inevitable that the oil droplets, which are the coarse particles, would drip onto the inner peripheral surface of the combustion chamber, causing so-called incomplete combustion in which red flames would be generated and the combustion would occur. Therefore, it is not possible to greatly compare the combustion conditions, that is, it is not possible to obtain a large town-down ratio, and it is also not possible to obtain a large town-down ratio.
There were problems such as increased turbidity of Ox.

(Object of the Invention) An object of the present invention is to provide a liquid fuel combustion device in which incomplete combustion is unlikely to occur even if the combustion state is greatly restricted and the liquid fuel particles become coarse.

(Summary of the Invention) This invention provides a nozzle for injecting liquid fuel at a predetermined spray angle on the closed end side of a combustion chamber, which is open at one end in the axial direction and closed at the other end. A burner cone is installed coaxially with the nozzle so that the inner surface of the peripheral wall is formed at approximately the same angle as the spray angle of the nozzle, and the inner surface of the peripheral wall does not contact the outer peripheral surface of the fuel injection area determined by the spray angle of the nozzle. This burner cone prevents incomplete combustion.

(Embodiment of the Invention) A first embodiment of the invention will be described below with reference to FIGS. 1 and 2. The combustion apparatus shown in FIG. 1 includes a main body 1. A cylindrical combustion tube 3 whose one axial end surface is closed by an end plate 2 is provided inside the combustion tube 3 with its open end surface exposed to the outside. A separate air passage β is formed.Combustion air □ is sent to this air passage 4 by a blower (not shown), and this combustion air is sent to the axially open end of the peripheral wall of the combustion tube 3. The air flows into the inside of the combustion tube 3, that is, into the combustion chamber 6, through an air hole 5 drilled on the side.

A nozzle 7 is provided at the center of the end plate 2 with its tip facing the combustion chamber 6. This nozzle 7 is pipe-connected to a fuel tank 9 via a pump 8. Therefore, when the pump 8 is operated, the liquid fuel contained in the fuel tank 9 is atomized and injected from the nozzle 7 at a predetermined spread angle θ. This expansion angle θ is maintained when the discharge pressure of liquid fuel by the pump 8 is equal to or higher than a predetermined value. Further, a burner cone 1 is provided on the closed end side of the combustion chamber 6, that is, closer to the nozzle 7 than the air hole 5.
1 is provided. This burner cone 11 is made of a heat-resistant material, such as a porous ceramic material, and has an inner circumferential surface having an angle that is approximately the same as or slightly larger than the injection angle θ of the liquid fuel from the nozzle 7. It is shaped like a funnel. This burner cone '11 has an inner surface of its peripheral wall at a spray angle θ of the nozzle 7.
The fuel injection area is arranged so as not to contact the outer peripheral surface of the fuel injection area determined by the fuel injection area. Furthermore, a concave flame stabilizer 12 is disposed on the open end side of the combustion chamber 6, facing the burner cone 11. This flame holder 12 is a burner cone 1
Like 1, it is made of a heat-resistant material such as porous ceramic material.

According to the combustion apparatus configured in this way, the pump 8 is operated to inject liquid fuel from the nozzle 7 at a predetermined pressure, that is, at an angle θ, and at the same time, the combustion air is caused to flow out from the air hole 6. Then, the atomized liquid fuel and air are mixed, this air-fuel mixture is ignited by an ignition device (not shown) and combusted, and the flame generated at that time is kept in a stable state by the flame stabilizer 12. It will be done. Further, by injecting the liquid fuel into the burner cone 11, the flow of the liquid fuel causes a negative pressure on the small diameter side, which is the base end side of the burner cone 11. Then, a flow is generated in the combustion chamber 6 from the tip side to the base end side of the burner cone 11 as shown by the arrow.
This flow re-purifies the unburned gas remaining in front of the burner cone 11, promoting combustion and preventing incomplete combustion.

Further, since the inner circumferential surface of the burner cone 11 has substantially the same angle as the fuel injection angle q·1 angle θ, the fuel injected from the nozzle 7 does not collide with the inner surface of the burner cone 11.

On the other hand, if the supply pressure of liquid fuel is lowered to narrow down the combustion state,
The particles of the fuel injected from the nozzle 7 become coarse and do not scatter forward sufficiently, causing the burner cone 11 to become injected as shown in FIG.
Drips onto the inner surface of the. This burner cone 11 is heated by the combustion flame and radiant heat from the flame stabilizer 12. therefore,
Since the coarse particle fuel dropped into the burner cone 11 is quickly vaporized and mixed with the combustion air from the air hole 5 and burned, incomplete combustion is prevented. In other words, even if the combustion conditions are greatly reduced and the particles of the liquid fuel become coarse, the fuel can be burnt satisfactorily. In other words, the towndown ratio of the combustion device can be increased.

3 to 5 show second to fourth embodiments of the present invention, respectively, and these embodiments differ from the first embodiment in the shape of the flame stabilizer 12. That is, in the second embodiment shown in FIG. 3, the flame stabilizer 12 is formed into a cylindrical shape with a bottom, and is arranged with its open end facing the burner cone 11 side. In FIG. 4, a deep flame device 12 is formed into a funnel shape smaller than the burner cone 11, and is arranged with its small diameter side facing the burner cone 11. In FIG. 5, the flame stabilizer 12 is formed into a cylindrical shape, and its axis is arranged along the axial direction of the combustion chamber 6.

〔Effect of the invention〕

As described above, the present invention provides a burner cone in which the inner surface of the peripheral wall is formed at almost the same angle as the injection angle of the nozzle, in the combustion chamber, and the inner peripheral surface of the burner cone is located around the outer circumference of the fuel injection area determined by the spray angle of the nozzle. It was placed coaxially with the nozzle without contacting the surface. Therefore, even if the particles of the liquid fuel become coarse by lowering the pressure of the liquid fuel and restricting the combustion state, the fuel drops onto the inner peripheral surface of the burner cone heated by the combustion flame, vaporizes, and burns. This can lead to incomplete combustion, producing red flames and soot.

In addition, when liquid fuel is injected into the burner cone, negative pressure is created on the inlet side of the burner cone, and the unburned gas that remains in front of the burner cone is recirculated and burned. Combustion is prevented and good combustion conditions are obtained. Furthermore, by providing the porous ceramic material in the combustion chamber, combustion noise, especially high frequency components, is reduced, so that a noise reduction effect can also be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the first embodiment of the present invention in a normal combustion state, FIG. 2 is a cross-sectional view of the same with combustion throttled, and FIGS. FIG. 7 is a cross-sectional view showing second to fourth embodiments. 6... Combustion chamber, 7... Nozzle, 11... Burner cone, 12... Flame holder.

Claims (3)

[Claims] (1) A combustion chamber with one axial end open and the other end closed;
A nozzle is provided on the closed end side of the combustion chamber and injects liquid fuel at a predetermined spray angle, and the inner surface of the peripheral wall is formed at approximately the same angle as the spray angle of the nozzle. A liquid fuel combustion device comprising: a burner cone disposed in the combustion chamber coaxially with the nozzle without contacting the outer peripheral surface of a determined fuel injection area. (2) The liquid fuel combustion device according to claim 1, characterized in that a flame stabilizer is disposed on the open side end face of the combustion chamber at a position facing the expanding side end face of the burner cone. . (3) The liquid fuel combustion device according to claim 1, wherein the burner cone is made of a porous ceramic material. (3) The liquid fuel combustion apparatus according to claim 2, wherein the flame stabilizer is made of a porous ceramic material.